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Speargun project

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
1570 total draw length - 100 mm for loops and wishbones = 1470. 1470 / 3 = 490

That's one length of rubber. There's 2 wishbones


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But as I said im not gonna argue, but thats always the way ive calculated bands for a roller.

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I'm sure you're right I just assumed it was the same for a roller I'll have to do some research... Oops


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Yeah I forgot the wishbones, my bad. You might be right, and so am I, guess it depends on how you work it.

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If your guns shoots straight, dont change a thing lol.

Any other rollergun user give us some knowledge about calculating band length?

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whitey180 said:
1570 total draw length - 100 mm for loops and wishbones = 1470. 1470 / 3 = 490

That's one length of rubber. There's 2 wishbones

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Click to expand...


That's in principle the same way as I calculated mine. You can always shorten them further if preferred.
Jégwan
 
If I can get away from doing paper work tonight and go though the go pro ill post a vid later on.


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I'm actually in the process of building another one, just a normal band gun. This time the stock will be a lot lighter and have a shaped muzzle. This new one is 30mm high and 35 wide at the muZzle tapering to 50 at the handle.


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Reactions: lawstraljan16 and Jegwan
You seem to like the idea of gun building whitey180 haha, same here. Sadly I dont have the tools to keep making them, but might invest in a router and some other useful tools for gun building

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I'm convinced that this gun doesn't shoot straight lol. I took it out for the second time yesterday and can't hit a broad side of a barn door. Maybe I just need to get used to the sight picture. I've since scalloped out the sides near the trigger mech so the bands can sit lower.


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I cant see the link, its broken. Are you shooting straight but low by any chance? Also, what band/shaft size you using?

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" "

I'm not sure, maybe I just need more practice with the gun. It seemed to dip to one side actually but the flopper was hanging down and not tucked up.

It's 2x16mm @300% 7.5mm shaft


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Link still not working lol. Thats the problem with rollerguns. The bands could be a little too hard, softer bands like Alemanni bands are the best, and they get them from America so you might be able to find some. When I had my rollergun I made a slowmotion video where I had the camera fixed on the seabed showing the gun from the side, and noticed that when shooting the tip of the gun would tilt before the shaft leaves the gun completely and would direct the shaft downwards. Are you shooting low?

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Nah I'm not shooting low, I went out the other day and out of 15 shots missed every time. This isn't the roller gun this is my second one. I want to get this right first and the next one make a roller. The first one tuned out to be a boat of a gun lol


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Great with a video. Thanks.

Some thoughts..

I take that the spear you are using are 100% straight.

The rubber/spear setup sounds ok.
It looks the recoil makes the gun muzzle move a little down and to the left. Are the handle and barrel fully parallel/perpendicular/on same centreline? (it might not mean that much for the shooting performance/accuracy - if you know how to aim with the gun - but it can confuse the aim a lot).

The spear you use is quite short (little overhang) and it's a (not very long) midhandle gun. I think that this combination makes it more difficult to aim correct. A little twist/a few degree angle on the wrist/aim will mean a lot on the distance.

Jégwan
 
That's very interesting. I never thought about it like that. A similar analogy when comparing say a handgun to a rifle. I will check the handle tonight. Also at the time of those videos the front of the gun was floaty. It's been ballasted correctly now so perhaps this should improve things.


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